## 9.21

Boltzmann Equation for Entropy: $S = k_{B} \ln W$

Leah Savage 2F
Posts: 74
Joined: Fri Sep 29, 2017 7:06 am

### 9.21

Nanotechnologists have found ways to create and manipulate structures containing only a few molecules. However, orienting the molecules in speci c ways to assemble such structures can be difficult. Calculate the entropy of a solid nanostructure made of 64 molecules in which the molecules (a) are all aligned in the same direction; (b) lie in any one of four orientations with the same energy.

How do you know the kb for the equation in this problem?

Lisa Tang 1C
Posts: 62
Joined: Fri Sep 29, 2017 7:05 am
Been upvoted: 2 times

### Re: 9.21

Kb is Boltzmann's constant, so it is 1.381 x 10-23 J/K. It doesn't change from problem to problem. Hope this helps!

Maeve Gallagher 1J
Posts: 56
Joined: Fri Sep 29, 2017 7:07 am

### Re: 9.21

In this case kb is Boltzmann's constant, 1.38x10^-23 J/K

Jessica Wakefield 1H
Posts: 58
Joined: Thu Jul 27, 2017 3:00 am

### Re: 9.21

Kb is Boltzmann's constant, so it is 1.381 x 10-23 J/K but you can still solve part a even if you didn't know that because Kb is multiplied by ln 1 which is 0 so your answer is 0 regardless

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